Adhesive formulations for carpets

ABSTRACT

The invention is a formulation for use in the manufacture of carpets. The formulation is combined with polymers such as, but not limited to, ethylene vinyl acetate (EVA, a co-polymer) to provide carpet backing formulations which exhibit excellent tensile strength. The formulation of the invention can be provided to carpet manufacturers as a separate product to be added later to a polymer for a use in carpet backings. Alternatively, the formulation can be added to a polymer such as EVA or compositions comprising EVA and then applied to a carpet backing to provide a carpet with a carpet backing exhibiting excellent tensile strength.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

FIELD OF THE INVENTION

The invention relates to products used in carpet backing applications.

BACKGROUND OF THE INVENTION

As noted in U.S. Pat. No. 5,560,972, carpet construction can vary but generally a pile carpet is generally manufactured in one of two ways. The pile yarn may be woven or tufted through a primary backing. The yarn is then secured to the primary backing with an adhesive. This type of carpet in which yarn is mechanically as well as adhesively attached to backing is generally termed “woven” or “tufted” carpet.

Alternatively, yarn may be cut or looped and positioned to form a pile layer that is then secured to the primary backing with adhesive. Carpet of this type is commonly referred to as “fusion bonded” carpet.

Fusion bonded carpet is generally categorized by the way the pile yarn layer is produced. In an “I-tuft” process, yarn is first cut into short, straight strands, and then the yarn ends are bonded to a primary support backing with adhesive. In a “U-tuft” process, a pile yarn layer is formed of folded yarn strands. The folded sections of the strands are then secured to the primary backing with an adhesive layer such that in the final carpet product, both ends of each cut strand protrude from the adhesive base.

Fusion bonded carpets typically used a non-latex PVC (polyvinyl chloride) plastisol formulation as the bonding adhesive. Typically, PVC plastisol is dispensed over a support layer to form an adhesive layer that penetrates into the support layer. The adhesive layer is then contacted with pile forming yarn. The PVC plastisol is cured, creating a product in which the yarn fibers are secured in the PVC layer and thereby bonded to the support layer. Increased strength may be obtained by bonding a secondary backing to the support layer.

In order to make a durable fusion bonded carpet in which the support layer does not peel away from the secondary backing, the adhesive which has permeated into the support layer must contact and bond with the material forming or adhering the secondary backing. The use of a non-latex plasticized PVC as the yarn locking adhesive limits the variety of backing structures that may be applied to the carpet. This is true because non-latex PVC plastisol does not bond strongly to common carpet backing materials such as bitumen, EVA (ethylene-vinyl acetate), APP (atactic polypropylene), hot melts, urethanes, and SBR (styrene-butadiene). Furthermore, SBR (styrene-butadiene) is relatively expensive, and PVC plastisol is both relatively expensive and presents environmental concerns due to its chloride content.

A fusion bonded carpet which does not use PVC as the pile yarn adhesive is described in U.S. Pat. Nos. 4,371,576 and 4,576,665. The carpet is prepared by forcing a heated hot melt adhesive through a liquid permeable support layer to contact with the pile forming yarn on the opposite side of the base layer. The adhesive is then allowed to cool, during which time the pile forming yarn and support layer are secured.

Hot melt adhesives have been known for many years and usually include a thermoplastic resin, wax and a polymeric adhesive. Typically such compositions have a melt viscosity of significantly less than about 200,000 cps, and more typically, less than 100,000 cps at 300.degree. F., to enable them to have sufficient flow characteristics at the application temperature. Hot melt adhesives are applied at high temperature, and cured by cooling.

U.S. Pat. No. 3,775,366 discloses a process for crosslinking compounds based on triazines with natural and synthetic rubbers. More specifically, the '366 is directed to a process of cross-linking synthetic rubber containing fillers or mixtures containing these materials without the use of elemental sulfur with heat and possibly pressure. The new kind of crosslinking (as defined in the '366 patent) provides products with considerable advantages and properties.

U.S. Pat. No. 5,206,304 describes the use of bis(2,4-organylthio-s-triazine-6-yl) polysulfides as accelerators in vulcanizable rubber mixtures including SBR.

U.S. Pat. No. 5,560,972 discloses a fusion bonded carpet in which the pile yarn is secured in a non hot-melt latex adhesive base and methods of manufacture of such carpet. The '972 patent notes that crosslinking of a latex adhesive with the aid of compounds such as melamine is beneficial to prevent softening and degradation of the adhesive layer on exposure to water (column 9, lines 28-31). Specific examples of copolymers include vinyl acetate-ethylene and styrene-butadiene, as well as blends of these compounds (see column 2, lines 32-37).

U.S. Patent Publication Number 20080233336 discloses modular carpet tiles having multiple layers. Preferably, a pre-coat layer includes a latex polymer compounded optionally with at least one filler, at least one flame retardant, and/or at least one additive, or any combination thereof. The latex polymer can include, but is not limited to, a vinyl acetate-ethylene (VAE) latex, an acrylic latex, a styrene-butadiene-rubber (SBR) latex, or any blend thereof (paragraph [0056]).

U.S. Patent Publication Number 20080113146 pertains to carpet and methods of making and recycling carpet. In one aspect, the carpet includes: a primary backing which has a face and a back surface; a plurality of fibers attached to the primary backing and extending from the face of the primary backing and exposed at the back surface of the primary backing; an adhesive composition backing; and an optional secondary backing adjacent to the adhesive backing. In claim 37 of the '146 patent publication a pre-coat material as claimed recites a combination of VAE emulsion and SBR latex.

None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention.

SUMMARY

The invention is a formulation for use in the manufacture of carpets. The formulation is combined with polymers such as, but not limited to, ethylene vinyl acetate (EVA, a co-polymer) to provide carpet backing formulations which exhibit excellent tensile strength. The formulation of the invention can be provided to carpet manufacturers as a separate product to be added later to a polymer for a use in carpet backings. Alternatively, the formulation can be added to a polymer such as EVA or compositions comprising EVA and then applied to a carpet backing to provide a carpet with a carpet backing exhibiting excellent tensile strength.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic in which a blend of EVA-ANS of the present invention already applied as a coating to the inner surface of the primary backing of a carpet.

FIG. 2 shows a table (TABLE 1) of test results.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

The invention is a formulation for use in the manufacture of carpets. The formulation is combined with polymers such as ethylene vinyl acetate (EVA, a co-polymer) to provide carpet backing formulations which exhibit excellent tensile strength. The formulation of the invention can be provided to carpet manufacturers as a separate product to be added later to EVA or compositions comprising EVA to provide carpets with carpet backings exhibiting excellent tensile strength. The formulation of the invention is referred to as “ANS”, “229” and “the product from Saudi” in the attached Appendices. The designations “229” and ‘the product from Saudi” were used to ensure that the technicians involved in carrying out ASTM standard testing were not aware of the makeup of composition “229”; this ensured necessary secrecy during testing of the formulation. However, with the filing of this patent application the make-up of 229 is listed in Appendix C wherein “229” is referred to with the preferred designation: “ANS” which are the initials of the inventor Abdulaziz Nasser Alsoryai. ANS combined with EVA provides a synthetic latex that is cheaper than SBR and enables favorable filler ratios to be used in carpet backing such as, but not limited to, 500 and 550 filler loads; however, ANS combined with EVA provides a carpet backing effective at 600 and 700 filler loads.

To aid the reader, Table 1 shows a summary of lab test findings taken from Appendix A. The results shown in Table 1 data demonstrate that adding ANS to EVA provides a product with favorable tensile strength and decreased elongation and as such ANS enables EVA (i.e., in the form of an EVA-ANS blend which can be applied as a coating to the inner surface of the primary backing of a carpet (see FIG. 1) thereby reducing or removing the need for SBR (SBR or VAE can be applied as a secondary coating to the inner surface of the secondary backing in which case the EVA/SBR blend can bond with the secondary backing). SBR is a more expensive than the EVA-ANS blend of the present invention.

The Appendices attached hereto form part of the description of the preferred embodiments of the invention. It should be understood that the number “229” and phrase “from Saudi” found in the “Summary of Lab notes” in Appendix B refers to the ANS formulation listed in Appendix C.

The invention being thus described, it will be evident that the same may be varied in many ways by a routineer in the applicable arts. Such variations are not to be regarded as a departure from the spirit and scope of the invention. 

1. An adhesive formulation 1 comprising (1) de-mineralized water at about 30 wt % to about 40 wt %; polyvinyl alcohol at about 1 wt % to about 5 wt %; potassium persulphate at about 0.05 wt % to about 0.20 wt %; sodium bi-carbonate at about 0.10 wt % to about 0.30 wt %; EM-031 non-ionic emulsifier at about 0.15 wt % to about 0.45 wt %; GEOwet ionic emulsifier at about 0.15 wt % to about 0.45 wt %; BYK®-037 defoamer at about 0.01 wt % to about 0.10 wt %; Safolite at about 0.005 wt % to about 0.05 wt %; and Nipacide Cxf 4 antibacterial at about 0.10 wt % to about 0.30 wt %.
 2. The adhesive formulation 1 according to claim 1 wherein the de-mineralized water is about 41 wt %; the vinyl acetate monomer is about 55 wt %; the polyvinyl alcohol is about 2.5 wt %; the potassium per sulphate is about 0.1 wt %; the sodium bi-carbonate is about 0.16 wt %; the EM 031 at about 0.3 wt %; the GEOwet ionic emulsifier is at about 0.3 wt %; the BKY®-037 defoamer is at about 0.04 wt %; the sodium sulphoxylate is at about 0.01 wt %; and the Nipacide Cxf 4 antibacterial is at about 0.17 wt %.
 3. An adhesive formulation 2 (ANS), comprising (1) the adhesive formulation 1 according to claim 1; (2) a plasticized carpet latex; (3) a waterproof additive; (4) a defoamer; and (5) an antibacterial.
 4. The adhesive formulation 2 (ANS) according to claim 3, wherein the plasticized carpet latex is Starfix-FA-A-36 resin.
 5. The adhesive formulation 2 (ANS) according to claim 3, wherein the waterproof additive is Starbond-30-36 resin.
 6. The adhesive formulation 2 (ANS) according to claim 3, wherein the defoamer is BKY®-037 defoamer.
 7. The adhesive formulation 2 (ANS) according to claim 3, wherein the antibacterial is Nipacide Cxf
 4. 8. The adhesive formulation 2 (ANS) according to claim 3, wherein the adhesive formulation 1 is from about 45 wt % to about 85 wt % of ANS.
 9. The adhesive formulation 2 (ANS) according to claim 3, wherein the plasticized carpet latex is Starfix-FA-A-36 (resin) that is from about 10 wt % to about 35 wt % of ANS.
 10. The adhesive formulation 2 (ANS) according to claim 3, wherein the plasticized carpet latex is Starfix-FA-A-36 (resin) comprising about 50 wt % of solids.
 11. The adhesive formulation 2 (ANS) according to claim 3, wherein the waterproof additive is Starbond-30-36 resin that is present at about 5 wt % to about 20 wt % of the ANS.
 12. The adhesive formulation 2 (ANS) according to claim 3, wherein the defoamer is BKY®-037 defoamer that is present at about 0.05 wt % to about 0.5 wt % of ANS.
 13. The adhesive formulation 2 (ANS) according to claim 3, wherein the antibacterial is Nipacide Cxf 4 that is present at about 0.05 wt % to about 0.5 wt % of ANS.
 14. The adhesive formulation 2 (ANS) according to claim 3, wherein the adhesive formulation 1 is about 66 wt % of ANS; the plasticized carpet latex is Starfix-FA-A-36 resin (49 wt % solids) at about 22 wt % of ANS; the waterproof additive is Starbond-30-36 resin at about 12 wt % of ANS; the defoamer is BKY®-037 at about 0.1 wt % of ANS; and the antibacterial is Nipacide Cxf 4 at about 0.1 wt % of ANS.
 15. An adhesive formulation 2 (ANS), comprising (1) the adhesive formulation 1 according to claim 2; (2) a plasticized carpet latex; (3) a waterproof additive; (4) a defoamer; and (5) an antibacterial, wherein the adhesive formulation 1 is about 66 wt % of ANS; the plasticized carpet latex is Starfix-FA-A-36 resin (49 wt % solids) at about 22 wt % of ANS; the waterproof additive is Starbond-30-36 resin at about 12 wt % of ANS; the defoamer is BKY®-037 at about 0.1 wt % of ANS; and the antibacterial is Nipacide Cxf 4 at about 0.1 wt % of ANS.
 16. A product comprising ANS according to claim 3 and ethyl vinyl acetate (EVA).
 17. The product according to claim 16, further comprising a filler, wherein the filler comprises water, calcium carbonate, a thickener; and a defoamer.
 18. The product according to claim 17, wherein the ratio of ANS to EVA ranges from about 5:1 to about 7:1.
 19. A product containing a 550 filler load with 80% EVA and 20% of the ANS according to claim
 3. 20. A product containing a 500 filler load with 80% EVA and 20% of the ANS according to claim
 3. 